Evidence for Mass-dependent Circumstellar Disk Evolution in the 5 Myr Old Upper Scorpius OB Association

By J. Carpenter, Eric Mamajek, L. Hillenbrand, M. Meyer. 2006

254 citations recorded by the source corpus.

We present 4.5, 8, and 16 μm photometry from the Spitzer Space Telescope for 204 stars in the Upper Scorpius OB association. The data are used to investigate the frequency and properties of circumstellar disks around stars with masses between ~0.1 and 20 M☉ at an age of ~5 Myr. We identify 35 stars that have emission at 8 or 16 μm in excess of the stellar photosphere. The lower mass stars (~0.1-1.2 M☉) appear surrounded by primordial optically thick disks based on the excess emission characteristics. Stars more massive than ~1.8 M☉ have lower fractional excess luminosities suggesting that the inner ~10 AU of the disk has been largely depleted of primordial material. None of the G and F stars (~1.2-1.8 M☉) in our sample have an infrared excess at wavelengths ≤16 μm. These results indicate that the mechanisms for dispersing primordial optically thick disks operate less efficiently, on average, for low-mass stars, and that longer timescales are available for the buildup of planetary systems in the terrestrial zone for stars with masses ≲1 M☉.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/234e2956fc141c4539039d5f3c95ce95321ca9c4

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In Astronomy and Astrophysics

1. K. Luhman
2. Eric Mamajek
3. L. Hillenbrand
4. L. Hartmann
5. G. Herczeg
6. N. Evans II
7. S. Andrews
8. P. Myers

Citations in the corpus

• PHOTOEVAPORATION OF CIRCUMSTELLAR DISKS BY FAR-ULTRAVIOLET, EXTREME-ULTRAVIOLET AND X-RAY RADIATION FROM THE CENTRAL STAR (2008, background): “Carpenter et al. (2006) report disk fractions as a function of stellar mass for the 5 Myr Upper Sco association and they find that at least the inner disks (as probed by mid-IR dust emission) are longer lived for low-mass stars (0.1–1.2 M ) and for more massive stars (1.8–20 M ), and are shortest…”
• Spitzer Observations of the Orion OB1 Association: Disk Census in the Low-Mass Stars (2007, background): “The trend toward higher masses has been observed in several stellar groups (e.g., Hernández et al. 2005; Sicilia-Aguilar et al. 2006; Carpenter et al. 2006).”
• NEW DEBRIS DISKS AROUND YOUNG, LOW-MASS STARS DISCOVERED WITH THE SPITZER SPACE TELESCOPE (2009, unknown): “In the 3–5 Myr Upper Sco association, Carpenter et al. (2006) observes that primordial disks continue to persist in an optically thick state around K and M dwarfs, but have already transitioned to optically thin disks around earlier type stars.”
• THE ROLE OF MULTIPLICITY IN DISK EVOLUTION AND PLANET FORMATION (2011, methodology): “In contrast, the disk frequencies for Upper Scorpius and NGC 2362 (τ∼5 Myr) are only ∼5–10% in this mass range (Carpenter et al. 2006; Dahm & Hillenbrand 2007; Currie et al. 2009).”
• THE DISK POPULATION OF THE UPPER SCORPIUS ASSOCIATION (2012, methodology): “Spitzer has been used to identify and classify disks in Upper Sco based on mid-IR photometry (Carpenter et al. 2006, 2009; Chen et al. 2005, 2011; Riaz et al. 2009) and to study the mineralogy of dust in those disks with mid-IR spectroscopy (Scholz et al. 2007; Dahm & Carpenter 2009).”
• THE RUNTS OF THE LITTER: WHY PLANETS FORMED THROUGH GRAVITATIONAL INSTABILITY CAN ONLY BE FAILED BINARY STARS (2009, background): “In contrast, typical core accretion times increase with radius and exceed 10 Myr beyond 20 AU (e.g. Levison & Stewart 2001; Goldreich et al. 2004).”
• Pre-main-sequence isochrones - II. Revising star and planet formation time-scales (2013, background): “…to far-IR Spitzer observations of lowmass pre-MS stars indicate that by 5 Myr approximately 80 per cent of primordial discs have dissipated (e.g. Carpenter et al. 2006; Dahm & Hillenbrand 2007), agreeing with estimates based on nearIR observations (e.g. Haisch, Lada & Lada 2001; Hillenbrand…”
• A Spitzer View of Protoplanetary Disks in the γ Velorum Cluster (2008, background): “We include recent Spitzer results for the young stellar clusters NGC 1333 (Gutermuth et al. 2007), NGC 2068/71(Flaherty & Muzerolle 2007), Taurus (Hartmann et al. 2005), NGC 7129 (Gutermuth et al. 2004), Chameleons (Megeath et al. 2005a), Tr 37 and NGC 7160 (Sicilia-Aguilar et al. 2006), IC 348 (Lad”
• Variations on Debris Disks: Icy Planet Formation at 30-150 AU for 1-3 M☉ Main-Sequence Stars (2008, background): “In addition to the long-term time evolution of mid-IR excess, the data also indicate a large range in the 24Y70 m excess at fixed stellar age (Rieke et al. 2005; Carpenter et al. 2006; Su et al. 2006; Currie et al. 2008a).”
• A STEEPER THAN LINEAR DISK MASS–STELLAR MASS SCALING RELATION (2016, background): “Carpenter et al. (2006) found that the fraction of optically thick disks in UpperSco is higher for K+M dwarfs (∼0.1–1Me) than for earlier spectral type stars.”
• A REVISED AGE FOR UPPER SCORPIUS AND THE STAR FORMATION HISTORY AMONG THE F-TYPE MEMBERS OF THE SCORPIUS–CENTAURUS OB ASSOCIATION (2011, result): “This compares well with the Carpenter et al. (2006) Spitzer results in which 0/30 (<11%; 95% C.L.) Fand G-type stars were found to be accretors.”
• A Spitzer Space Telescope Study of Disks in the Young σ Orionis Cluster (2007, background): “…results for the young stellar clusters NGC 7129 (Gutermuth et al. 2004), Taurus (Hartmann et al. 2005), Chameleonis (Megeath et al. 2005a), Tr 37 and NGC 7160 (Sicilia-Aguilar et al. 2006), IC 348 (Lada et al. 2006), and Upper Scorpius (Carpenter et al. 2006) have been included in this plot.”
• The Formation and Early Evolution of Low-Mass Stars and Brown Dwarfs (2012, methodology): “We also include new disk fractions for Upper Sco based on WISE photometry (K. Luhman, in preparation, see also Carpenter et al. 2006).”
• Protoplanetary Disks and Their Evolution (2011, background): “In their study of the 5Myr old Upper Scorpius OB association, Carpenter et al. (2006) obtained 4.5, 8.0 and 16µm photometry of 204 members with masses ranging from ∼ 0.1 to 20M⊙.”
• The Spitzer c2d Survey of Weak-Line T Tauri Stars. II. New Constraints on the Timescale for Planet Building (2007, background): “Given the very different spectral type distribution of our sample (there are only 7 objects with types later than K0 in our sample), our result does not contradict those presented by Carpenter et al. (2006).”
• ALMA OBSERVATIONS OF CIRCUMSTELLAR DISKS IN THE UPPER SCORPIUS OB ASSOCIATION (2016, methodology): “While ∼ 65% of low-mass stars in Taurus host an optically thick inner disk (Hartmann et al. 2005), this fraction has decreased to ∼ 19% in Upper Sco (Carpenter et al. 2006).”